1. Field of the Invention
This invention relates to bottom-hole assemblies used in oil and gas wells, and more particularly, to a check enhancer having an outer body with ports longitudinally spaced from ports in a dispersement nipple of the apparatus.
2. Description of the Prior Art
It is well known in the production and treatment of oil and gas wells to inject fluids into the well. This is done in a variety of ways, one of which is to use a bottom-hole assembly. Prior art bottom-hole assemblies comprise a ball check valve attached to a ported dispersement nipple. The ball check valve is connected to a length of coiled tubing by a known tubing fitting. The coiled tubing is used to run the tool into the well to a desired location. In operation, fluid is flowed down the tubing into the bottom-hole assembly. The fluid passes through the ball check valve which allows flow downwardly therethrough and prevents any significant amount of fluid from flowing back upwardly through the tubing. The fluid flows out of the bottom-hole assembly through the ports in the dispersement nipple and into the well at a location adjacent to the bottom-hole assembly.
These prior art bottom-hole assemblies have had a couple of problems. First, scale deposits due to contaminants in the well can build up in the ports in the dispersement nipple, and this will eventually restrict the flow therethrough. If this occurs, it may be necessary to remove the assembly from the well prematurely for cleaning. This is both costly and time consuming.
Another problem with the prior art bottom-hole assembly is that bubbles may form in the dispersement nipple. These bubbles can float up within the dispersement nipple and pass upwardly through the ball check valve, either when the ball check is open to flow fluid therethrough or because a complete seal may not be formed in the valve when it is closed. These bubbles can disrupt the flow through the tubing.
The present invention solves these problems by adding an outer housing around the prior art bottom-hole assembly. The body keeps clean fluid around the check valve and dispersement nipple which significantly reduces or eliminates scale deposits in the check valve and nipple ports. Also, the presence of fluid adjacent to the dispersement nipple minimizes bubble formation. Bubbles may form at the ports in the outer housing, but even if this occurs, the bubbles will merely float up to the upper inside portion of the outer housing which is not a problem because that portion of the housing is not in communication with the tubing.
The present invention is an improved bottom-hole assembly, and more specifically, as used herein, a check enhancer apparatus for use in injecting fluids into a well. The enhancer generally comprises a housing portion defining a fluid cavity therein and a housing port in communication with the fluid cavity, a length of tubing connected to the housing portion such that a portion of the tubing extends into the fluid cavity, and an injector portion disposed in the fluid cavity and connected to the portion of the tubing in the fluid cavity. The injector portion define an injector port therein in communication with the tubing and the fluid cavity, and the injector port is longitudinally spaced from the housing port.
The housing portion comprises an outer body in which the housing port is disposed and an adapter connected to the outer body and the tubing. The adapter defines an opening through which the tubing is slidably disposed. The injector portion comprises a dispersement nipple in which the injector port is disposed and a check valve connected to the dispersement nipple and the portion of the tubing extending into the fluid cavity.
The check valve, preferably either a ball check valve or poppet-type valve, allows fluid flow from the tubing to the dispersement nipple and substantially prevents fluid flow from the dispersement nipple to the tubing. The housing port is preferably located above the injector port when the apparatus in disposed in the well, such that fluid flowing out of the injector port at least partially fills the fluid cavity before flowing out of the housing port. In one embodiment, the injector port is one of a plurality of injector ports, the housing port is one of a plurality of housing ports and all of the housing ports are longitudinally spaced from all of the injector ports.
Stated another way, the present invention is a check enhancer comprising a dispersement nipple defining a nipple port therein, a check valve connected to the dispersement nipple and adapted for connection to a length of tubing such that the nipple port is in communication with the tubing when the check valve is in an open position, and an outer body disposed around the dispersement nipple and the check valve, the outer body defining a body port therein. The body port is longitudinally spaced from the nipple port, and in the preferred embodiment, the body port is above the nipple port when the apparatus is positioned in the well. The nipple port is preferably one of a plurality of nipple ports defined in the dispersement nipple, the body port is one of a plurality of body ports defined in the outer body, and all of the body ports are longitudinally spaced from all of the nipple ports. The check valve is attached to the tubing by a tubing fitting.
The enhancer further comprises an adapter connected to the outer body and adapted for connection to the length of tubing. The tubing is slidably disposed through the adapter such that the dispersement nipple and the check valve may be longitudinally moved in the outer body. The adapter is attached to the tubing by a tubing fitting, and the check valve is attached to the tubing by another tubing fitting.